Field of the invention
This application relates to an imaging device for a microscope as well as a microscope incorporating the imaging device.
Brief Description of the Related Art
A microscope is a scientific instrument that is used to image objects, which either are too small themselves or have details that are too small to be visible to the naked eye. There are many types of microscopes available on the market. The most common of these and the first to be invented is the so-called optical microscope, wherein light that is reflected or transmitted by illuminated samples is imaged by a system of lenses to produce magnified images of the samples. The image from the optical microscope can be either viewed through an eyepiece or, more commonly nowadays, captured by a light-sensitive camera to generate a so-called micrograph. The images were previously captured on photographic film, but modern developments in charge-coupled device (CCD) cameras allow the capture of digital capture and storage of digital images.
The illumination sources used in optical microscopes have been developed over the years and wide varieties of illumination sources are currently available, which can emit light or other types of radiation at different wavelengths. Optical filters can be placed between the illumination source and the sample to be imaged in order to restrict the wavelength of the radiation illuminating the sample.
Modern biological microscopy uses fluorescent probes for imaging specific structures within a cell as the sample. In contrast to normal transilluminated light microscopy, the sample in fluorescence microscopy is illuminated through an objective lens with a narrow set of light wavelengths. These narrow set of light wavelengths interact with fluorophores in the sample, which then emit light of a different wavelength. This emitted/fluoresced light is used to construct the image of the sample.
U.S. Pat. No. 7,710,642 and U.S. Pat. No. 7,502,164 (Lytle at al., assigned to Westover Scientific, Mill Creek, Wash.) teach an illumination system for a fluorescent microscope. The illumination system disclosed in these two US patents include a carriage that is removably receivable within the microscope and a plurality of filter “cubes” that are arranged on the carriage. Each one of the filter cubes is movable between an active position and an inactive position. The filter cube comprises a housing, with first and second openings, as well as a solid-state light source secured to the housing. The solid-state light source emits radiation when the filter cube is moved into the active position. The filter cube further comprises at least one optical filter, which is disposed within the housing.
International patent application No. WO 2012/051718 teaches an automated slide scanning system for a microscope. The automated slide scanning system has an illumination system to illuminate an object, carried on a slide and to produce a returning light. A slide dispenser is configured to hold a plurality of slide holders, which are stacked vertically within the slide dispenser. A motorized scanning track is configured to pull the slide holder out of the slide dispenser onto the scanning track and to move the slide holder in one direction along an axis to image the object carried on the slide holder.
A paper by Moser at al. entitled “Filter Cubes with built-in ultrabright Light-Emitting Diodes as exchangeable Excitation Light Sources in Fluorescence Microscopy”, published in the Journal of Microscopy, vol. 222, Part 2, May 2006, pages 135-140, teaches the use of ultrabright light-emitting diodes as a potential substitute for conventional excitation light sources in fluorescence microscopy. The ultrabright light-emitting diodes were integrated into a filter block of a conventional fluorescence microscope together with a collimating Fresnel lens, a holographic diffuser and emission filters.
U.S. Patent Application No. U.S. 2012/0326055 (Wilson et al, assigned to University Health Network) teaches a system for sub-surface fluorescence imaging with an excitation source and a light detector. The excitation source is a broadband light source and has an excitation filter wheel located in front of the broadband light source. The excitation filter wheel can filter light from the broadband light source at at least two excitation wavelengths. The light from the light source is projected onto a fairly large area of the sample.
International Patent Application No. WO 01/73374 (Büchler) discloses a measuring microscope with an electronic cameral that can be moved in any one of three axes about an object using drives.
One of the issues with the microscopes of the prior art is the need to move a sample into position for imaging. This movement (which involves both acceleration and deceleration of the sample) may result in distortion of the sample due to forces asserted on the (small) sample. The imaging of the sample is as a result not as accurate as it might otherwise have been.